JP-8-327698-A describes a circuit simulation method which is capable of making a design taking into consideration self-heat generation of a circuit in which a plurality of circuit elements are connected. This circuit simulation method first calculates the magnitude of current and voltage of each circuit element, which forms part of the circuit, at temperature T which is given when self-heat generation is not taken into consideration (first step). Then, the circuit simulation method senses the magnitude of current flowing through each circuit element, which varies depending on the power consumption of the circuit, calculates temperature variation ΔT from a variation in power consumption of the circuit due to this variation in current, and sets the temperature (T+ΔT) to new temperature T (second step). The voltage or current can be calculated taking into consideration the heat generated by the circuit element by alternately repeating the first and second steps until the circuit state converges.
JP-11-175576-A in turn discloses a system for verifying a layout using a heat circuit network. This layout verification system first creates a circuit diagram from the result of a layout performed based on logic circuits, and calculates a current density of each wiring segment using the circuit diagram. Next, the system creates a heat circuit from the circuit diagram, calculates the temperature of each wiring segment using the heat circuit, and derives an allowable current density of each wiring segment based on that temperature. Then, the system compares the current density of each wiring segment derived from the circuit diagram with the allowable current density of each wiring segment derived from the heat circuit for verification.